Faults with Car - which should've been fixed

On the 21st of January 2022 - I bought a used Dodge Journey using finance option from Webuycars Germiston. Initially the car had a check engine light flagged as part of the Dekra report I asked the sales agent assisting me (Frans Aphane) if this will be sorted and he said all Dekra highlighted issues will be cleared as part of the Finance process. Upon receiving the car on the 21st of Jan 2022, the check engine light was off. Less than 3 weeks of owning the car on the 4th of February the check engine light returned - I then called the Innovation Group, with whom I took the compulsory Warranty with and they said i should take the car for a diagnostic at the local dealership. The dealership found that the Oil cooler with the sensor and gaskets are faulty and this will result in an almost R10 000 repair cost - meaning that the check engine light was just cleared and the faults not fixed. Innovation group do not cover this work nor do they cover the cost of the diagnostic (R850). I am now looking at a heavy cost from something that was a) flagged in the Dekra report and never cleared and b) something I was assured was fixed before taking the delivery of the vehicle. This is really not ideal and very disappointing as I had a very positive experience with Arista and Frans and for it to be undone by such issues is disappointing.